document.write( "Question 634984: To solve this you want to write it:
\n" ); document.write( "x^4 + 11x^2 - 80 = 0 \n" ); document.write( "
Algebra.Com's Answer #400076 by lwsshak3(11628)\"\" \"About 
You can put this solution on YOUR website!
solve for x
\n" ); document.write( "x^4 + 11x^2 - 80 = 0
\n" ); document.write( "**
\n" ); document.write( "let u=x^2
\n" ); document.write( "u^2=x^4
\n" ); document.write( "..
\n" ); document.write( "u^2+11u-80=0
\n" ); document.write( "(u+16)(u-5)=0
\n" ); document.write( "..
\n" ); document.write( "u=-16=x^2
\n" ); document.write( "x=±√-16
\n" ); document.write( "x=±4i (non-real solution)
\n" ); document.write( "..
\n" ); document.write( "u=5=x^2
\n" ); document.write( "x=±√5
\n" ); document.write( "check:
\n" ); document.write( "(x^4 + 11x^2 - 80 = 0
\n" ); document.write( "(√5)^4+11(√5)^2-80
\n" ); document.write( "25+55-80=0\r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "
\n" );